Field of the Invention
The present invention relates to a silicone composition superior in thermal conductivity; and a semiconductor device.
Background Art
Most electronic parts generate heat while in use. Thus, it is required that heat be removed from these electronic parts for the purpose of appropriately operating the same. Particularly, with regard to an integrated circuit element such as a CPU used in a personal computer, the amount of heat generated therefrom has increased due to an increased operation frequency thereof, thus making a countermeasure(s) against heat a critical issue.
Therefore, there have been proposed many methods for releasing such heat. In the case of an electronic part generating a particularly large amount of heat, there has been proposed a method for releasing the heat by interposing a thermal conductive material such as a thermal conductive grease or a thermal conducive sheet between the electronic part and a member such as a heatsink.
JP-A-Hei-2-153995 discloses a silicone grease composition obtained by combining a particular organopolysiloxane and a spherical hexagonal aluminum nitride powder with a given particle diameter. JP-A-Hei-3-14873 discloses a thermal conductive organosiloxane composition obtained by combining an aluminum nitride powder with a smaller particle diameter and an aluminum nitride powder with a larger particle diameter. JP-A-Hei-10-110179 discloses a thermal conductive silicone grease obtained by combining an aluminum nitride powder and a zinc oxide powder. JP-A-2000-63872 discloses a thermal conductive grease composition employing an aluminum nitride powder surface-treated by an organosilane.
The thermal conductivity of an aluminum nitride is 70 to 270 W/mK. As a material having a thermal conductivity higher than this range, there can be listed diamond which has a thermal conductivity of 900 to 2,000 W/mK. JP-A-2002-30217 discloses a thermal conductive silicone composition obtained by combining a silicone resin with a diamond, a zinc oxide and a dispersant.
Further, JP-A-2000-63873 and JP-A-2008-222776 disclose a thermal conductive grease composition obtained by mixing a base oil such as a silicone oil and a metallic aluminum powder.
Furthermore, there have also been disclosed, for example, JP-B No. 3130193 and JP-B No. 3677671, where a silver powder with a high thermal conductivity is used as a filler.
However, none of these thermal conductive materials or thermal conductive greases has been able to sufficiently cope with the amount of heat generated in a recent integrated circuit element such as a CPU.